The invention relates to a front attachment for a self-propelled combine harvester for harvesting stalked crop such as corn or sunflowers. The front attachment comprises a plurality of intake conveyor mechanisms arranged side by side and each comprising grooved conveyor wheels that rotate about a substantially vertical rotational axis. The front attachment further comprises snapping units located downstream of the intake conveyor mechanisms in the direction of crop flow that comprise snapping rollers extending horizontally and transversely to the direction of travel and, a transverse conveyor. The transverse conveyer is equipped with opposing auger sections, via which harvested corn cobs or fruits from sunflowers are drawn together in the center of the front attachment and fed from there to a feed rake. The grooved conveyor wheels of the individual intake conveyor mechanisms comprise, on the outer circumference thereof, radially extending driving elements, which engage via sections thereof into guide channels to pick up and convey corn plants or sunflowers. The guide channels are oriented substantially in the direction of travel in the inlet region thereof and, in the outlet region thereof, in the direction of a snapping gap formed between the snapping rollers.
Corn is cultivated in rows separated by substantially constant distances, wherein sowing is carried out by sowing individual seeds, and the corn plants that have gone to seed reach a height of up to three meters. The corn plant substantially comprises a corn stalk, corn leaves having a length of up to one meter, and fruits in the form of corn cobs enclosed by husks. There are two main types of corn harvesting, namely, harvesting using a corn harvester to fragmentize the entire corn plant, including the corn kernels, to permit the subsequent use thereof as feed, in the form of corn for silage. In fragmentized form, the corn plant also can be supplied as biomass to biogas plants. The corn harvesters used to harvest the corn plants process the entire corn plant, as explained previously, and therefore the fruit (that is, the corn cobs comprising the corn kernels), do not need to be removed from the remaining plant components.
In contrast, a combine harvester is used to harvest grain corn that is typically equipped with a front attachment for harvesting corn or sunflowers instead of the usual header thereof that is used to harvest grain. The front attachment ensures that the entire plant is drawn in a controlled manner into a snapping unit in which the fruits are removed from the stalks of the plant and are subsequently fed by way of a feed rake to a threshing mechanism of the combine harvester.
There are front attachments that are suited exclusively to harvesting the corn plants in a row-dependent manner. Therein, individual intake conveyor mechanisms must be adjusted according to the distance between the rows, and the combine harvester must be operated with the front attachment oriented according to the rows. Various attempts to develop a row-independent harvesting procedure in which the harvesting machine does not need to follow the row crop exactly are known. Such known processes, however, are fraught with considerable problems because it must be ensured that the corn plants that are not located in a row extending continuously with respect to the particular intake conveyor mechanism are captured by same and are subsequently fed to the downstream snapping units.
A front attachment for a combine harvester that is provided for harvesting grain corn is known from DE 10 2009 051 053 A1. Distributed along the width thereof is a plurality of intake conveyor mechanisms, which form guide channels and are separated from one another. Each of the intake conveyor mechanisms comprises a plurality of rotating grooved conveyor wheels, which are disposed on substantially vertical rotational axes, capture the corn plant at the corn stalk thereof and subsequently transport them through the particular guide channel. Different groups of intake conveyor mechanisms having different arrangements of the grooved conveyor wheels also are provided. An intake conveyor mechanism disposed in the center of the front attachment and intake conveyor mechanisms positioned on both sides thereof work together. The intake conveyor mechanisms capture the corn plants and convey them through the two guide channels in the end sections thereof, which point outwardly relative to the center intake conveyor mechanism and the center of the front attachment.
In the known front attachment, only four crop inlet openings are provided and, instead of the individual, outwardly located grooved conveyor wheels, intake conveyor mechanisms that correspond to the design of the centrally located intake conveyor mechanism are required to increase the working width of the front attachment. In this case as well, the crop flow would be conveyed outwardly once more by the guide channels formed as a result, in the end section thereof.
A similar arrangement of intake conveyor mechanisms of a front attachment for harvesting grain corn is known from DE 10 2005 021 792 A1. In that case, however, each of the intake conveyor mechanisms comprises two grooved conveyor wheels, which are driven in opposite directions. The intake conveyor mechanisms disposed on both sides of a longitudinal central plane likewise ensure that the corn plants fed into the center are transported toward the outside.
Furthermore, EP 1 106 049 A1 discloses a front attachment designed to permit harvesting to be carried out in a row-independent manner. In that case, each of the intake conveyor mechanisms are driven in the same direction and have upper and lower tine rotors that are curved in different directions in the end regions thereof. A snapping unit, which extends in the direction of travel, is disposed next to each of the tine rotors, from the snapping plates thereof outward the harvested corn cobs are fed to a downstream transverse conveyor. The corn stalks and the corn leaves that are drawn through the snapping gap reach a chopper, which is located underneath the snapping plates, fragmentizes the components and deposits them onto the field.